Embedded Files
"The indicator sponge is saturated with Congo red solution. Congo red is a dye, a biological stain, and a pH indicator. It has been used as a direct fabric dye for cotton to produce a bright red fabric. Biologists use Congo red as a general contrast stain for cellulose. Congo red is also used as a pH indicator. The color transition is between pH 3.0 and 5.0. Below a pH of 3.0 (very acidic solutions), the indicator is blue. Above pH 5.0, the indicator is red.When a cellulose sponge is soaked in a Congo red solution, the dye becomes permanently bonded to the cellulose fibers. The active acid/base sites on Congo red are still available and the sponge now becomes an indicator sponge for acids. It can also be used to check for acid spills on counters after students have used acids."
Introduction
Welcome to my site, my PBL project is about "Indicator sponge" as the name say's its basically a sponge which indicates acids/bases. In this project I will do magic by changing colors with sponge and beaker, keep on reading to know the answered if you dare. Hope you enjoy learning more about it and have fun.
*Please do not try it at home*
Driving Question:
How do bases and pH levels work? When is it used and for what is congo red?
Materials
Materials
Congo red indicator
Hydrochloric acid
Sodium hydroxide
Red food coloring
Blue food coloring
Indicator sponge
Beaker or a large jar
Sponge
Tongs or Gloves
SAFETY PRECAUTIONS:
"Hydrochloric acid is corrosive to skin and eyes and toxic by ingestion and inhalation. Sodium hydroxide solution is corrosive
to skin and eyes. Wear chemical splash goggles, chemical-resistant gloves, and a chemical-resistant apron. Please review current. Material Safety Data Sheets for additional safety, handling, and disposal information."
Flinn Scientific, Inc.
Preparation
Preparation
Before you start have supervision of some one adult and me cautious of what are you doing.
1) 100 mL of one M hydrochloric acid to a beaker in between 1000 or 2000 mL, filling the beaker 3/4 full with water
2) Add 1 mL per 1000 mL to acid solution in beaker until a red dark color comes out.
3)add 100 mL of 1 M sodium hydroxide solution to the beaker filling it about 3/4 full.
4)Add blue food coloring to the beaker until its a dark blue color.
5)The sponge is red so wet the sponge and tap water rinsing it out.
6)Now if the sponge is blue, placing the sponge in the solution becoming the blue color into red.
Procedure
Procedure
1) Red sponge is placed into beaker which has red acid solution. *Please use gloved or tongs for safety* Wow Sponge transforms into blue!
2)Remove the sponge and SQUEEZE IT (make sure to squeeze it very well or else it won't work and you might start all over) taking out as much red acid into the acid beaker.
-optional: you can have an extra beaker where you have water and you can take the excess of the sponge with acid
4)Now slowly place the blue sponge into the beaker with blue base *using gloves or tongs* Magic sponge transforms into red!
5)Remove sponge and squeeze out the blue base into the blue beaker.
6)Rinse it in water and show how the sponge is red and its not saturated with red solution.
7)Repeat it as many times you want.
To watch the video please go to: Indicator Sponge Video
So how indicator use? It weaknesses acids and change slightly alkaline conditions, the weak bases change under slightly acidic.
pH what is that? pH is the measure in activity hydrogen ion. Solutions with pH greater than 7 are known as basic or alkaline.
Why acid-base indicator?
acid-base indicator weak base and acid but a indicator can make change color from acid to alkaline by a hydrogen ion concentration. Color change interval is also well known as pH range.
Congo red Indicator: Indicator for pH levels
Color change on a pH range: 3.0-5.0
Color of acid: blue
Color of base: red
Page updated
Google Sites
Report abuse